I don't view Drake's equation as a formula, more of a jumping-off point for conversation / contemplation. It would be more difficult to comprehend and communicate the concepts without that 'calculation'.
Debating the finer points of you critiques is the only value the equation has (to me at least, I know nothing of Drake or his works).
I think we have evidence that gravity exists outside of our galaxy.
You've never been there, you don't know for sure. It could be some other phenomenon and it just looks similar to our galaxy.
Assuming that gravity works in other galaxies is exactly that; an assumption. It's a good assumption because every other observation we've ever made about the laws of physics and such support it, and there's nothing ever been observed to indicate that it's a bad assumption.. but it's still just an assumption, one that giving provisional support to makes sense.
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Originally Posted by Knalus
Have you not noticed that discussing the existence of Alien life is one of those topics that serious scientists all seem to accept as not just plausible and probable, but move beyond that into likely?
They do? A biologist giving a talk about convergent evolution in the context of speculation about aliens to try and appeal to a lay-audience certainly doesn't do that, and that's where you started out.
But if I had to choose, I'd probably choose likely as well, at least given what we currently know.
From a simple probability point of view, given an infinite universe anything that isn't impossible will be duplicated.
And in a finite universe, the probability that things would turn out so that there'd only be exactly one planet where life arose is like walking on the edge of a knife (far more probably to have either no life, or lots of life), something to be very suspicious of and certainly not a place to start from. And since we know that we exist... We have no good reason to think we're in a unique situation here.
If you reach into a box filled with a trillion coloured marbles, and you know that the marbles can only be one of two colours, and you pull out a red one, the safe bet is to assume that the marbles are either all red, or a significant portion of them are. To bet that there's only one red one in the trillion and you just happened to get it isn't the safe bet. Without looking you can't know of course, and no one would make a definitive statement about the ratio of red marbles, but some possibilities are still preferred over others until more information is uncovered (like maybe red marbles and your hand attract each other).
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Originally Posted by Knalus
Even in the face of a complete lack of evidence?
Absence of evidence is not evidence of absence.
Not that that constitutes evidence that there is alien life.
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Originally Posted by Knalus
I wonder why that is. Can we not find wonder in our universe without conjuring up a multitude of imaginary beings flying all around the place? Does the universe really need dressing up in order to make it fun enough to involve the lay person? I personally don't think it does.
How do you go from not saying aliens and skeptic in the same breath to saying science conjures imaginary flying beings to create a sense wonder because they don't see enough already??
Life arose once, the universe is vast beyond imagining (maybe infinite), to think that the right circumstances for life arose exactly once (as opposed to zero or more than once) is the position that requires skepticism IMO.
__________________ Uncertainty is an uncomfortable position.
But certainty is an absurd one.
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Can we not find wonder in our universe without conjuring up a multitude of imaginary beings flying all around the place? Does the universe really need dressing up in order to make it fun enough to involve the lay person? I personally don't think it does.
Using a fried dough and Kit Kat stop-motion animation, the folks over at Elements explain how a synchroton particle accelerator—like the Large Hadron Collider—accelerate particles up to the speed of light.
With how much building blocks of life are found in meteors, I'd be stunned if life is commonplace in the universe, very basic life of course in that vast majority, and evolved intelligent life much less commonplace.
My thinking is basic life is probable to about .01% in the "Goldilocks" zone,if that planet that has basic life can survive for about a billion years..chances are it would have evolved intelligent life.
May seem to be a small number but it could possibly be 10's of thousands of planets in our galaxy alone that have intelligent life. If we talk the universe were taking billions.
One things for sure, none of us here today will be alive to find out and possibly no human ever will.
It's so hard to wrap our "pea-brains" on the vastness of space,our galaxy will collide with another in about 3 billion years(Andromeda) but chances are nothing will hit each other, we are talking billions upon billion of stars and their planets not even coming close to each other...that is vast! can the average person understand gravity? pull a dime out of your pocket...put it in the palm of your hand and then try to imagine it weighing as much as a large mountain...this is what a "dime" size peice of a nutron star weighs.
When will this collision occur? Plausible orbits and models of the Milky Way and Andromeda galaxies suggest that the big event could occur in as soon as 3 billion years. The Sun will still be burning brightly when this collision occurs and maybe life of some sort will still be around on Earth (or at least within the solar system) at that time. So what would people see in the night sky during this billion year galactic dance? As Andromeda approaches, it will grow in size and just before the collision the night sky will be filled by a giant spiral galaxy. When the two galaxies intersect, our familiar Milky Way arch over the sky will be joined by a second intersecting arch of stars but this will only last for 100 million years or so and will be a very confusing state of affairs for galactic astronomers. Finally, when the two galaxies merge our view will depend on which direction the Sun is thrown. There are two possible fates fort the Sun which depend closely on the details of where it is in its galactic orbit at the time of the collision. In the first case the Sun may take a ride on a tidal tail and be ejected into the darkness of intergalactic space. In this case, our star would be all alone with few stellar neighbours so the night sky would be very dark with few stars to see -- maybe like the disappointing view of the nightsky from an urban centre like downtown Toronto. In the second case, the Sun may be thrown right into the centre of the merging pair where a great starburst will be underway. The huge number of stars forming will result in supernovae going off at a rate of a few per year in the new merged galaxy. While these will likely not present a direct hazard to the Earth, they will truly light up the sky letting you read at night but probably frustrating the endeavours of backyard astronomers!
My thinking is basic life is probable to about .01% in the "Goldilocks" zone,if that planet that has basic life can survive for about a billion years..chances are it would have evolved intelligent life.
May seem to be a small number but it could possibly be 10's of thousands of planets in our galaxy alone that have intelligent life. If we talk the universe were taking billions.
One things for sure, none of us here today will be alive to find out and possibly no human ever will.
It's so hard to wrap our "pea-brains" on the vastness of space,our galaxy will collide with another in about 3 billion years(Andromeda) but chances are nothing will hit each other, we are talking billions upon billion of stars and their planets not even coming close to each other...that is vast! can the average person understand gravity? pull a dime out of your pocket...put it in the palm of your hand and then try to imagine it weighing as much as a large mountain...this is what a "dime" size peice of a nutron star weighs.
Crazy stuff.
It took life on Earth 4 billion years to evolve to the point of multicellular life, and 4.5 billion to evolve intelligence as we know it. It's just as difficult for us to wrap our brains around the shear length of time certain things take to happen.
With how much building blocks of life are found in meteors, I'd be stunned if life is commonplace in the universe, very basic life of course in that vast majority, and evolved intelligent life much less commonplace.
Wow did I miss a big mistake in my post, I meant to say if life Isn't commonplace in its most basic forms I would be surprised.
It took life on Earth 4 billion years to evolve to the point of multicellular life, and 4.5 billion to evolve intelligence as we know it. It's just as difficult for us to wrap our brains around the shear length of time certain things take to happen.
Those aren't linear events though.
Mass extinctions play perhaps the largest role in shaping ecosystems and evolution.
Billions of years is lots of time for cataclysmic biological resets.
P.S. That is reasoning on my part, I am not a scientist.
You've never been there, you don't know for sure. It could be some other phenomenon and it just looks similar to our galaxy.
One of the cool things about other galaxies is that we may be looking at antimatter galaxies and not even know it as they would be virtually indistinguishable.
The only clue would be a boundary where matter and antimatter are meeting and annihilating each other to produce gamma rays but in the vast expanse and void of the intersteller medium between galaxies, we may not be able to observe this.
Jupiter might be having a change of heart. Literally.
New simulations suggest that Jupiter's rocky core has been liquefying and mixing with the rest of the planet's innards. With this new data, astronomers hope to better explain a recent puzzling discovery of a strange planet outside of our solar system.
"It's a really important piece of the puzzle of trying to figure out what's going on inside giant planets," said Jonathan Fortney, a planetary scientist at the University of California Santa Cruz who was not affiliated with the research.
Conventional planetary formation theory has modeled Jupiter as a set of neat layers with a gassy outer envelope surrounding a rocky core consisting of heavier elements. But increasing evidence has indicated that the insides of gas giants like Jupiter are a messy mixture of elements without strictly defined borders.
This new research on a melting Jovian core bolsters a mixing model of gas giant planets and would provide another avenue for heavier elements to flow throughout the planet.
"People have been working on the assumption that these planets are layered because it's easier to work on this assumption," said Hugh Wilson, a planetary scientist at the University of California Berkeley and a coauthor of the new research appearing in Physical Review Letters.
Although scientists had previously toyed with the idea of melting cores in large planets, nobody sat down and did the necessary calculations, said Wilson.
Scientists have to rely on calculations of Jupiter's core environment because the conditions there are far too extreme to recreate on Earth. Wilson and his UC-Berkeley colleague Burkhard Militzer used a computer program to simulate temperatures exceeding 7,000 degrees Celsius and pressures reaching 40 million times the air pressure found on Earth at sea level.
Those conditions are thought to be underestimates of the actual conditions inside Jupiter’s core. Nonetheless, the authors found that magnesium oxide -- an important compound likely found in Jupiter's core -- would liquefy and begin drifting into Jupiter's fluid upper envelope under these relatively tame conditions.
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Mass extinctions play perhaps the largest role in shaping ecosystems and evolution.
Billions of years is lots of time for cataclysmic biological resets.
P.S. That is reasoning on my part, I am not a scientist.
I agree. Thing is, though, if that's the case why did it evolve when it did? What happened to make that particular stretch of time work for the evolution of multicellular life, but none of the others? If mass extinctions punctuated life prior to multicellular life (and that raises other questions on how mass extinction events may have affected single cell life compared to multicellular life), why did we not see any proto-multicellular life in older rocks? Perhaps we will, perhaps we won't.
The Ediacran fauna in particular holds great fascination for me, in that it is possibly multicellular life predating the Precambrian, but doesn't appear to have any descendants.
It's all totally fascinating. I nearly followed this line of study, but opted for a job in my field instead.
Anyways, sorry for the rant. I know it's not news.
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MIT researchers have shown, for the first time ever, that memories are stored in specific brain cells. By triggering a small cluster of neurons, the researchers were able to force the subject to recall a specific memory. By removing these neurons, the subject would lose that memory.
__________________ Uncertainty is an uncomfortable position.
But certainty is an absurd one.
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^ There's a fairly detailed article on this topic in Discover this month. Pretty interesting for a neuro-psych geek like me as they get right into the nitty gritty of the modes of memory formation and a competitive neuron model for explaining how particular neurons become associated with individual memories.
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onetwo and threefour... Together no more. The end of an era. Let's rebuild...
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I hope these brain memory neurons are available to purchase within 3 to 5 years.... maybe then I'll remember names, faces, and what I just ran upstairs to get.
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Now, just to temper your excitement, we should note that MIT’s subjects in this case are mice — but it’s very, very likely that the human brain functions in the same way. To perform this experiment, though, MIT had to breed genetically engineered mice with optogenetic neurons — and we’re a long, long way off breeding humans with optogenetic brains.
Stupid lab mice get all the breaks.
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I hope these brain memory neurons are available to purchase within 3 to 5 years.... maybe then I'll remember names, faces, and what I just ran upstairs to get.
Or maybe we can purchase neurons that have been pre-populated... with, for example, memories of vacationing on mars!
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